The present invention relates generally to the transmission of light and, more particularly, to an apparatus and method for generating a periodic optical signal about a 360xc2x0 arc.
It is common to use flashes of light to create an image, attract the attention of an observer or as a warning device. However, most high intensity flasher systems use a pulse of light generated by a lamp driven by a capacitor discharge system. The electrical energy is stored in the capacitor and then released to the bulb through the use of timing electronics. The bulb radiates in all directions (i.e., in 4xcfx80 steradians) which requires a large amount of energy in order for the intensity to be such that an observer can see it from a significant distance such as several hundred meters or more. Additionally, the current capacitive discharge systems sacrifice bulb life due to the transient nature of the discharge cycling. Still, another disadvantage of the current discharge type flashers is that they are limited in flash rate due to the charge/discharge cycle of the capacitors.
Accordingly, there remains a need for a low cost, light weight and efficient solution for a remote source optical flasher system which is suitable for use on various forms of vehicles, or even stationary structures such as buildings, and which operates more efficiently as an optical warning signal than previously developed optical warning devices.
The foregoing drawbacks are overcome by a rotating fiber flasher system in accordance with preferred embodiments of the present invention. The rotating fiber flasher system overcomes the aforementioned disadvantages as well as other disadvantages by producing an optical signal from an optical signal source which is input to at least one light guide which is supported by a support member. The light guide is positioned with its input end facing the optical source. The light from the optical signal source is directed by the light guide toward a plurality of optical fibers housed within a manifold. Successive flashes of light are transmitted through each of the plurality of optical fibers of the manifold by rotating the light guide relative the face of the optical fibers in the manifold. The light guide thereby enables the light from the input source to be directed to each of the optical fibers by means of a motor driven assembly which continuously rotates the support member supporting the light guide. By selectively controlling the speed of rotation of the motor driven assembly, the light from the input source can be scanned in a circular path across the optical fibers, thereby transmitting an optical signal into each fiber. The optical signals are then applied to a lens type illumination element. The illumination element causes the optical signal to be refracted or reflected therefrom at a predetermined angle, depending on which specific optical fiber provided the optical signal. As the support member is rotated, the optical signals passed through the optical fibers impinge the illumination element at different positions on the element, which produces flashes of light which are directed in a 360xc2x0 arc. To an observer, this appears as a periodic light flash at a given location.
The present invention thus operates with greater efficiency than previously developed optical flashing systems because the entire energy of the source signal is focused in only one direction at a given moment, rather than used to illuminate an entire hemispherical area (2xcfx80 steradians) continuously. Thus, a less powerful optical source can be used while the system is still able to provide an optical signal of sufficient strength to be visible at significant distances.